as of a person looking at all the videos, the technology could go through years of video in a matter of minutes. >> crime analyst our point to the pivotal role surveillance cameras play that identified the suspect in boston. and now, some san francisco is something about increasing the city's network of cameras. police chief greg suhr is one of them. he says it would help them better monitor events like the bay to breakers race. >> i would have to get someone a lot smarter than me an engineer if you will to look at what would be possible for us to a port everything into one location. and to be able to monitor major event. >> we live in the post see as i, mci has the television jurors want to see video and the dna. we do everything we do to get it for them. i do not think there is a person in this country did not watch the events of last week on fold and watch it on video. >> however, the aclu is word about how police might use the cameras and how long the department will keep the video on file. the chief says he is talking with city officials about his idea and hopes to move it forwa